The melting ice sheets seem to have caused the oceans to rise flooding Mesolithic (Middle Stone Age) sites on the coast of Korea. The following period, called the Neolithic or New Stone Age, saw the appearance of hand-made flat bottomed pottery. This early pottery was unmarked, but later on geometric designs were scratched into the clay. These designs show cultural links with the Ural-Altaic region (central Russia) where similar pottery was made.

New studies of genetics, although not precise, show that native Americans have more in common with the population that now lives in Mongolia than with the modern Siberians. This suggests that the first migrants to North America started in central Asia, and that the current inhabitants of Siberia were later arrivals. The studies also have shown more genetic diversity among native American people than expected, which questions the traditional theory that there were only one to three big migrations from Asia somewhere around 14,000 years ago. That and recent new archaeological finds in South America also suggest the first people who arrived in the Americas came as early as 40,000 years ago.

While the climate changes during the ice ages opened up a land bridge to between Asia and North America, it also created a huge ice shelf. The edge of the ice shelf is estimated to have been more than 1.5 kilometres high. So, even if people were able to cross into what is now Alaska and northern British Columbia, the ice wall blocked them off from moving farther into the interior of North America. However, there were warmer periods when the ice wall shrank, and this may have allowed people to cross over. People may also have used boats to travel along the coast and avoided the ice shelf that way. It is also possible that people knew how to travel over the open ocean more easily than we have thought likely.